A known parking assist device described in Japanese Patent Laid-Open Publication No. H11-208420 displays a target parking position designation display so that an operator designates a target parking position of a vehicle on a screen showing an image of the vehicle surroundings by a positional operation of the target parking position designation display on the screen. With the known parking assist device described in Japanese Patent Laid-Open Publication No. H11-208420, in case the designated leading path to the target parking position is generated by the calculation, it is judged that the parking to the target parking position is available to lead the vehicle to the target parking position along the generated leading path. In case the leading path to the target parking position is not generated by the calculation, it is judged that the parking to the target parking position is unavailable, and the transaction to lead the vehicle is not conducted.
As foregoing, with the known parking assist device described in Japanese Patent Laid-Open Publication No. H11-208420, the availability of the parking to the designated target parking position is judged based on the availability of the leading path to the target parking position. In this case, the leading path is calculated using a neutral position at which the steering angle is defined zero or an actual steering angle at the time as a steering angle initial value of the vehicle at a start of the leading. Notwithstanding, because the foregoing calculation method limits the range of the leading path to be effectively generated, in practice, it is judged that the effective leading path is not generated and that the parking to the target parking position is difficult or impossible even when the parking to the target parking position is available by slightly changing the steering angle initial value.
A need thus exists for a parking assist device which expands the available range of a leading starting position for parking a vehicle to a target parking position.